Electronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some user interfaces, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) are also provided to the user, more generally known collectively as “haptic feedback” or “haptic effects.” Haptic feedback can provide cues that enhance and simplify the user interface. For example, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices to alert the user to specific events, or provide realistic feedback to create greater sensory immersion within a simulated or virtual environment.
In order to generate vibration or other effects, many devices utilize some type of actuator or other haptic output device. Known actuators used for this purpose include an electromagnetic actuator such as an solenoid actuator, an Eccentric Rotating Mass (“ERM”) actuator in which an eccentric mass is moved by a motor, a Linear Resonant Actuator vibration motor (“LRA”), an electro-active polymer actuator, and a piezoelectric actuator.